Vibrational monitor of early demineralization in tooth enamel after in vitro exposure to phosphoridic liquid

• Molecular-scale evaluation of the in vitro demineralization process was obtained.
• An increase in off-stoichiometry of the enamel surface structure was found.
• Raman spectroscopic algorithm allows a prompt non-contact diagnosis.

The Raman spectroscopic method has been applied to quantitatively assess the in vitro degree of demineralization in healthy human teeth. Based on previous evaluations of Raman selection rules (empowered by an orientation distribution function (ODF) statistical algorithm) and on a newly proposed analysis of phonon density of states (PDOS) for selected vibrational modes of the hexagonal structure of hydroxyapatite, a molecular-scale evaluation of the demineralization process upon in vitro exposure to a highly acidic beverage (i.e., CocaCola™ Classic, pH = 2.5) could be obtained. The Raman method proved quite sensitive and spectroscopic features could be directly related to an increase in off-stoichiometry of the enamel surface structure since the very early stage of the demineralization process (i.e., when yet invisible to other conventional analytical techniques). The proposed Raman spectroscopic algorithm might possess some generality for caries risk assessment, allowing a prompt non-contact diagnostic practice in dentistry.

Graphical AbstractOriginally smooth surface of the tooth suffered the acidic attack and was clearly corroded within a relatively short exposure time of 30 min.Figure optionsDownload as PowerPoint slide